1. Field of The Invention
The present invention relates to a cross flow fan, preferably of an indoor unit of an air conditioner, provided with fan blades having an improved shape.
2. Related Art
An air conditioner has an indoor unit and an outdoor unit, and many of the indoor units are generally provided with cross flow fans.
Such cross flow fan in a prior art is provided with a plurality of fan blades each having a cross sectional shape shown in FIG. 10, for example. In the illustration of the sectional view, a fan blade 11 is divided into symmetrical two parts by a dividing vertically at its central portion with a division line L so as to provide the same arcuate chord length of the blade 11. Such sectional shapes of both the portions have outer and inner peripheral arc portions substantially parallel to each other and substantially the same thickness along the blade chord direction. A cross fan blade having such structure is, for example, disclosed in Japanese Patent Laid-open Publication No. HEI 10-131886.
However, in such structure of the cross fan blade, in a case where an air suctioning port of the cross flow fan becomes subject to a high load due to an influence of a heat exchanger and a suction filter, it tends to increase an air blasting noise and increase a load to be applied on a fan driving motor, thus deteriorating an operational performance of the air conditioner itself.